Microscope fine focus control mechanism

Abstract

A monoaxial adjusting system is provided for accomplishing both coarse and fine focusing adjustments between the nosepiece and stage of a microscope. The coarse adjustment is made by rotation of either of two coarse adjusting knobs which in turn directly rotates a coarse adjusting shaft and cam. Suitable linkage is connected to the cam to affect linear movement between the nosepiece and stage. Fine adjustment is made through rotation of either of two fine adjusting knobs which actuate the coarse shaft and cam through a planetary gear reduction system and follower. A further adjusting mechanism is lever operated so that the operator may easily provide fine adjustment while manipulating the North-South stage and East-West slide control knobs. The entire adjusting system is spring and gravity loaded to eliminate backlash.

What is claimed is: 
     
       1. In an optical instrument having a support and an adjusting system supported thereby, said system having at least one shaft and mechanism cooperatively engaged thereto for providing relative movement between the instrument's optics and an object being examined, a fine focusing control mechanism comprising: a rotatable member eccentrically positioned between said at least one shaft and said support for accomplishing fine focusing whereby rotation of said rotatable member displaces said at least one shaft with respect to said support a sufficient amount such that said mechanism imparts fine focusing movement.   
     
     
       2. The optical instrument fine focusing control mechanism as set forth in claim 1, wherein said rotatable member comprises an eccentric bushing and includes projection means on said bushing to enable the operator to readily grasp said projection means to rotate said eccentric bushing. 
     
     
       3. The optical instrument fine focusing control mechanism as set forth in claim 2, wherein said projection means comprises an actuating lever. 
     
     
       4. The optical instrument fine focusing control mechanism as set forth in claim 1, wherein stop means is provided for cooperative engagement between said support and said rotatable member whereby said stop means prevents said rotatable member from rotating past a preselected point. 
     
     
       5. The optical instrument fine focusing control mechanism as set forth in claim 4 wherein said stop means comprises a pin projecting from said support column and being received within a slot formed in said rotatable member. 
     
     
       6. The optical instrument fine focusing mechanism as set forth in claim 5, and futher including friction means for cooperative engagement between said column and said rotatable member whereby rotation of said rotatable member is prevented when said at least one shaft is rotated by knobs affixed thereto yet being rotatable when force is applied directly thereto. 
     
     
       7. The optical instrument fine focusing system as set forth in claim 6, wherein said friction means is affixed to said projecting pin.